ISO/TR 20173:2018

Overview

ISO/TR 20173:2018 - Welding - Grouping systems for materials - American materials is a Technical Report that provides an American-style grouping system for materials used in welding and allied processes. Classified in accordance with the grouping system of ISO/TR 15608:2017, the document lists ferrous and non‑ferrous materials (Tables 1 and 2) commonly used in North America and additionally includes a number of Canadian, Australian and New Zealand specifications. It is informational (no normative references or listed terms) and is intended to support classification, material selection and compatibility decisions rather than to impose prescriptive test methods.

Key topics and technical content

• Material grouping system: Presents American grouping identifiers mapped to ISO/TR 15608 groups for both ferrous and non‑ferrous materials.
• Material families covered: steel; aluminium and its alloys; nickel and its alloys; copper and its alloys; titanium and its alloys; zirconium and its alloys; cast irons.
• Tables and cross‑references: Tables provide mappings between American standard specifications (ASTM, ASME, API, AAR, ABS, CSA, AS/NZS, MSS, NACE, etc.), UNS/type or grade designations and nominal compositions.
• Scope of applicability: While focused on welding, the grouping system is explicitly applicable to other processes such as heat treatment, forming, and non‑destructive testing (NDT).
• Document status and updates: This is the third edition (2018), replacing the 2009 edition; main technical updates include a complete revision of Tables 1 and 2 and editorial layout changes.

Practical applications

• Welding procedure development and qualification: Use groupings to determine which base materials belong to the same welding group for Procedure Qualification Records (PQRs) and Welding Procedure Specifications (WPS).
• Filler‑metal and consumable selection: Help select compatible filler metals and assess weldability across related material grades.
• Heat treatment and forming planning: Guide decisions where material families respond similarly to thermal and mechanical processing.
• NDT and inspection planning: Grouping assists in anticipating inspection needs and interpreting expected material behaviors.
• Procurement and specification: Standardize material calls in contracts by referencing grouping identifiers rather than single proprietary grades.
• Material traceability & interchangeability: Facilitate cross‑referencing between American standards and international group classifications.

Who should use this standard

• Welding engineers and inspectors
• Procedure writers and QA/QC teams
• Materials engineers and metallurgists
• NDT specialists
• Purchasing/specification engineers
• Standards committees and regulatory bodies working with American, Canadian, Australian and New Zealand material specifications

Related standards and references

• ISO/TR 15608:2017 - Basis for the grouping system used in ISO/TR 20173:2018.
• Work prepared by ISO/TC 44, Welding and allied processes; cross‑reference relevant national standards (ASTM, ASME, API, AAR, ABS, CSA, AS/NZS, MSS, NACE) for specific material specifications.

Keywords: ISO/TR 20173:2018, welding grouping systems, American materials, ISO/TR 15608, ferrous and non‑ferrous grouping, material classification for welding, filler metal selection, WPS, welding engineers.